1. Field of the Invention
The present invention relates generally to defect inspection apparatus for bottles made of such transparent material as glass bottles, for example, and is especially related to bottle defect inspection apparatus that use such photoelectric conversion sensor like television cameras.
2. Description of the Prior Art
Those dealers that are engaged in handling glass bottles which are used to preserve and sell spirits, beverages or liquids or the like, are necessitated with sufficient cautions in handling such bottles. Especially, as for the bottle mouth conditions, if there are breakage, chips, cracks or defects or the like, at the ossasions of filling the fluid and/or capping the bottle, various trouble will occur due to incomplete capping, whereas the content liquid will leakout during transportation of the bottles, or it could be dangerous when the bottle mouth contacts the human mouth or lip. Especially when recycled or refilling type bottles are recollected for reuse, during the circulation of these bottles, the bottles often are damaged especially at the mouth portion so that, attention must be provided to whether the bottle mouth portion has a defect or not.
Therefore, at fluid production plants such as breweries or the like, prior to filling the bottle with liquid after washing the bottles, for example, it was customary that visual inspectors that depend upon their visual sights, checked the damages at the bottle mouth portion and removed the ones that were judged as a defective bottle.
It was through the recent years that in order to replace the human inspection, the bottle defects, especially the mouth portion defects thereof are detected photoelectrically by photoelectric conversion means such as photoelectric sensors and defective bottles were automatically rejected came into practical use.
The conventional methods that are used to detect bottle mouth defects photoelectrically are such that light is irradiated onto the bottle mouth from the top or side thereof, the reflection light thereon is picked up to be converted into electrical signals by such photoelectric conversion sensor means like a photosensors or video cameras that are placed on the top or at the side of the bottle mouth, and such electrical signal is processed by an electronic processor such as a computor as an example, to electrically judge whether or not there is a defect or abnormality at the bottle mouth.
However, as shown on FIG. 1, there were such defects as F at a mouth portion 2c of a bottle 2 as one example, that are cracks on a very smooth surface (not complexed) or those that are vertical thin crack lines that go down from the bottle mouth 2c as shown on FIG. 2, or otherwise are hidden by an upper edge portion 2c.sub.1, that sticks out at the bottle mouth 2c as shown on FIG. 3, whereas the reflection light from the defects F do not reach the defect detection section such as photoelectric sensors that are placed above the top of the mouth portion 2c, so that the conventional apparatus that depend upon the reflected light from the defects, carry the fault that such defect detection was difficult.
Next, with reference to FIG. 4, one example of such above mentioned conventional bottle mouth defect detection device will be explained. In FIG. 4, 1 is a photoelectric conversion sensor such as a television camera or the like, which is placed above the top of bottle mouth 2c of the bottle 2 to be inspected. 3 is an electronic processor which electrically processes the electrical signals from the television camera 1, 4 is a circular light source that is placed above the top of the inspected bottle 2, but is under the television camera 1.
According to this conventional example, by the light source 4 such as a fluorescent circuline as an example, the bottle mouth 2c of the bottle 2 is irradiated whereas such reflection light therefrom is picked up by the television camera 1, which is converted into electrical signals which are processed by the electronic processor 3, to thereby detect the existence or not of defects around the bottle mouth portion 2c of the bottle 2.
According to the conventional bottle mouth flaw inspection devices as said hereabove, when the defect F at the mouth portion 2c of the bottle 2 to be inspected is very smooth surfaced, or is a thin lined vertical crack that goes down from the bottle mouth 2c of the bottle 2, or when it is located inside and under the bottle mouth top outer edge 2c.sub.1 of bottle mouth 2c of bottle 2, although the light from light source 4 that is placed above the bottle mouth 2c of bottle 2, arrives at the bottle mouth 2c of bottle 2 and reflects on defect F, such reflection light will not reach the photoelectric conversion sensor 1 such as the television camera, and accordingly the detection of the defects was impossible.